Principles of Information Technology Chapter 1 Computer Basics

Principles of Information Technology Chapter 1: Computer Basics

What is a computer? § A computer is a machine that changes information from one form to another by performing four basic actions. Input, processing, output, and storage are the four actions of a computer’s information processing cycle. Input is the raw information, or data, that is entered into a computer. It can be simple (such as letters and numbers) or complex (such as photographs). 1

Input § Data is entered into a computer using code, and that code is made up of bits. “Bit” is short for binary digit. Each bit has two possible values: 0 or 1. § Pieces of data are entered into the computer as combinations of bits, or as 0 s or 1 s. The bits are combined into groups of eight or more. Each group is called a byte.

Computer Types § There are two kinds of computers Analog computers measure data on a scale with many values Digital computers work with data that has a fixed value

SKIP THIS SLIDE§ Color can be represented by a three-byte combination where each byte represents red, green, or blue (RGB). § There are 256 possible combinations of 1 or 0 in each group of eight bits. To represent a color, the three byte RGB codes are simplified into a 6 -digit hexadecimal value. The first two digits of the hexadecimal value represent the intensity of the red, the second two are green, and the last two are blue.

Processing § Computer instructions depend on the program given to the computer. The instructions are written in binary code using combinations of 0 s and 1 s. § Computers can process data rapidly, performing millions of operations every second. Speed of processing is one reason why computers are so valuable. § Once the data has been processed, storage saves the information in a permanent place for continued access. § After the computer processes data, output is created. Output can take many forms, such as an image or document.

What is Computer Hardware? § Hardware the computer’s physical parts. The processor is a hardware device that turns raw data into usable information. § Most computer hardware is inside the computer case. This hardware is used for processing and storing data. There are other devices, such as a keyboard or mouse, that are only used outside of the computer case.

Central Processing Unit § One of the most important processing devices to a computer is the central processing unit, or CPU. The CPU is attached to a circuit board, and is covered in tiny electrical circuits that quickly carry information in specific ways that allow the computer to do arithmetic and compare data quickly.

Data Storage § Near the CPU is the primary data storage area called random access memory, or RAM. The close proximity allows the CPU to quickly find the data it works with. § RAM stores data when the computer is on, but the data is lost when the computer is turned off.

Secondary Storage § Other storage hardware allows storage of data permanently, even when the computer is turned off. These are called secondary storage devices. Examples of secondary storage devices include: CDs, flash drives, hard drives, external hard drives, memory cards, or cloud storage, which is online storage offered through various Web sites. Some of these types of external storage connect to the computer via a universal serial bus, or USB port.

Which type of storage is best? § Hard disk drives hold the most data, typically in the amount of several hundred gigabytes. A gigabyte is just over a billion bytes. Some external hard drives can store more than 30 terabytes (tb). A terabyte is about 1, 000 gigabytes.

Hardware Peripherals § Input (such as keyboard and mouse) and output (such as monitors and printers) devices are typically separate from the case for most desktop systems. These are separate pieces of hardware, but can be connected to the case. This is called a peripheral. § Peripherals need to be connected to the computer for data to move back and forth. The connection can be via plug or wireless connection. Some peripherals connect internally, or are built-in.

Chapter Review (continued) § Primary storage, or RAM, is inside the case and loses data when the computer is turned off. Secondary storage is inside the case, though some have access to the outside and continue to store data when the computer is turned off. § System software, such as the Microsoft Windows operating system, helps the computer work properly. § Application software, such as productivity software, helps you complete tasks.